This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. As Mycobacterium bovis bacillus Calmette-Gu[unreadable]rin (BCG) is known to be safe and immunogenic, it is currently being explored as a vaccine vector to confer protection against various pathogens and cancer. But little has been done systematically to optimize their immunogenicity in nonhuman primates. We have generated a number of mutants of BCG vaccine vector that have improved immunogenicity in mice. These mutants have been constructed to express SIV antigens. In this study we are assessing the immunogenicity of four such mutants in nonhuman primates.